Known envelopes of the kind involved generally include:
a rear sheet, generally in plastic material, with glue on its external face, provided either with a slot for inserting the documents or a flap, glue coated or not, designed to close said envelope; PA1 a front sheet, generally in transparent plastic material pre-printed, integral with said rear sheet by means of lengthwise and crosswise tie bands on the contacting faces of said sheets, so that they form the properly so-called document envelopes; PA1 a laminar protecting support, generally in non adhesive paper of the silicone coated kind, located against the gluing face of the rear sheet and which includes or not a slot superimposed over the previous slot serving to insert the documents.
Said envelopes are always presented to be used one by one without any simple operating device having been devised namely for ungluing the silicone coated paper, introducing the documents and depositing the envelope on the object involved.
In its present manual use, handling times are very high, over all for the societies the business of which consists of the sales by mail or by the several quick shipping offices.